Apparatus for the electric transmission of signs or speech in mines.



J. H. RETNEKE APPARATUS FOR THE ELECTRIC TRANSMISSION OF SIGNS 0R SPEECHIN MINES.

APPLICATION FILED JULY 16, 1912.

Patented Mar. 14, 1916.

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JOSEF HEINRICH BEINEKE, OF IBOCHUM, GERMANY, ASSIGNOR- T'OSTUDIENGESELL- SCHAFT FUR DRAHTLOSE GRUIBENTELEFONIE M. B. H., OFCOLOGNE-LINDENTHAL,-

GERMANY.

-APPARATUS FOR THE ELECTRIC TRANSMISSION OF SIGNS OR SPEECH IN MINES.

Specification of Letters Patent. Patented Mar, 14, 1916.

Application filed July 16, 1912. Serial No. 709,660.

To all whom it may concern:

Be it known that-I, J OSEF HEINRICH REI- NEKE, engineer, residing atGraf-Engelbert strasse 33, Bochum, in Westphalia, Germany, have inventedcertain new and useful Improvements in Apparatus for the ElectricTransmission. of Signs or Speech in Mines, of which the following is aspecification.

The object of this invention is to provide improved means for theelectric transmission of graphic acoustic signals or speech in mines,whereby telephonic and telegraphic communications between under-groundlocalities and between such localities and the surface are facilitated.

The invention essentially consists in utilizing, as electric conductorsbetween the re ceiving and the transmitting stations, the existingmetallic connecting systems such as rails, pipes, haulage cables, andthe like, with the aid of electrostatically chargeable conductorsconnected to the terminals of .tween the transmitting station and theconductors, though possibly imperfect, directs the fiow of electricityso that signals can be received in a regular manner at difierent partsof the system. The special electrical conditions obtaining in mines arein this connection important, in that thebed-rock 1s,

face soil. This not only affords a kind of natural insulation, butestablishes a difference of conditions between the surface and theinterior of the mine. The surface soil,

the normal electrical state of which is disturbed by the working of thesystem, is not required to furnish a connection between the transmittingand receiving stations, but is used as a condenser of practicallyinfinite capacity. The charge imparted to the suras a conductor, muchinferior to the sur-" face soil is 'taken'up so rapidly, that acontinuous current can be obtained. In the mlne, an artificial condenserof wire fabric may be used, or part of the pipe system or the like notused as line conductor may furnish the condenser. ing, as indicated,allows of using a very simple form of transmitter. Irrespective whethercontinuous circuit or alternating current is employed, the transmittermay be an instrument having a primary circuit contaming the microphone!and battery, the secondary coil being connected at one end only to line.The rapid variations occurring 1n speech. acting on the transmitter,

{produce oscillations in the secondary coil,

which, in conjunction with the high potential of the charge, produceoscillations of the ether. The line and the secondary coil thus form alinear oscillator, which may have a gap or gaps without detrimentto thetransmission. The form and amount of energy required for thetransmission of graphic or acoustic signals are in general practicallythe same as in ordinary telegraphic and telephonic practice. 1

By reason of the fact that the current in the imperfect, and possiblyinterrupted, conductor has a definite value and direction, Whereas thepotential varies at different points, messages can be taken from theconductor by electrically bridging two points in series, between whichthere is an adequate potential difference and connecting a telephonic ortelegraphic'instrument to the connecting wire.

, The fact that the oscillations produced by the current fluctuationsgenerate fluctuating induction, lines may beutilizedby using a receiverwhich comprises antennae or an electric resonator whereby theoscillations are transmitted to a telephonic or other instrument. Thisis more particularly of advantage if the line is formed by a movingconductor, for eirample a haulage rope, or if the receiving station'ismoving, as for example on a tram; it is also convenient if the receivingstation requires to be shifted with facility, as for example at theworking face of the mine.

One form of apparatus for carrying the improved method into efiect isdiagrammatically illustrated in the accompanying The method of work- 50and operates the telephone.

drawing, which is an ideal vertical section of the mine.

.In this example the pipe R leading from the gallery Q through the shaftSch to the surface soil E is used as the line conductor,

and is connected to one end of the secondarycoil W of the transmittingstation V. The other end of this coil may be connected to a suitableelectrical counterpoise, as for example the conductor 0 having a largesurface capacity. The primary coil Z of the transmitter is connected tothe microphone M and the battery B. The lower end of thepipe R=isconnected to a conductor K having a large surface capacity, for examplea wire fabric,'or, as indicated by dotted lines, to the rails V. Thetelephone T is connected to the pipe R at w, y, so as to bridge aportion thereof. Another telephone T is connected by a Wire loop orantennae S located a certain distance from the pipe R,

and capable of being moved along. the line,

as for example by the car G.

Sound Waves acting on the microphone of the telephone used astransmitter produce oscillations of high pressure and frequency in thecoil W, and these are communicated by the pipe. The induction lines dueto the oscillating currents act on the resonator 'S,

to which thetelephone T is connected. It

does not matter if there is relative movement between the line and theresonator S, because the velocity of such movement is of course sosmall, compared with the velocity 85 of the electric oscillations, thatit can produce no perceptible.interference. Accordingl the haulage cableof the cage may be use instead. of. a stationary pipe, the telephone Tat the surfacebeing in that case 40 also served by1means of a'ntennae oraresonator.

' Another method of serving the telephone T at the surface consists injoining a good conductor L to the pipe R, below the upper end of thelatter, that is to sayin the shaft,

to secure by LettersPatent of the United States 1s: v

p 1. In the electric transmission of signs in subterranean mines,thecombination of the conventional conductive metal construction in mineservice with electrostatically chargeable conductors having largesurface capacities and with sign transmitting and sign receiving means.

2-. In the electrlc transmlsslon of slgns 1n subterranean mines, thecombination of the conventional conductive metal construction in mineservice with means for'connecting such construction near one terminalthereof With.the surface soil which constitutes an electrostaticallychargeable conductor having a large surface capacity.

3. In the electric transmission of signs in subterranean mines, thecombination of the conventional conductive metal construction 1n mineserv1ce with means for connecting such construction near one terminalthereof With the surface soil which constitutes an .current generator incircuit with said primary coil, and a secondary coil connected to theconductive metal construction.

5. In the electric transmission of signs in subterranean mines, thecombination of the conventional conductive metal construction in mineservice with electrostatically chargeable conductors having largesurface capacities, and with a transmitting station comprising a primarycoil, a mircophone and a current generator in circuit with said primarycoil, a secondary coil, an additional electrostatically chargeableconductor having a large surface capacity, and means for respectivelyconnecting the ends of said secondary coil to the conductive metalconstruction and to said additional electrostatically chargeableconductor.

6. In the electric transmission of signs in subterranean mines, thecombination of the conventional conductive metal construction in mineservice with electrostatically chargeable conductors having largesurface capacities, and with a receiving station comprising a telephone,and means for connecting said telephone to said conductive metalconstruction.

7 In the electric transmission of signs in subterranean mines, thecombination of the conventional conductive metal construction in mineservice with electrostatically chargeable conductors having largesurface capacities, and with a receiving station comprlsing a telephone,and means for. connecting said telephone in parallel to a section ofsaid conductive metal construction.

8. In the electric transmission of signs in subterranean mines,"thecombination of the conventional conductive metal construction in mineservice with electrostatically chargeable conductors having largesurface capacities, a transmitting station composed of a primary coil, amicrophone and a current generator in circuit with said primary coil,and of a secondary coil connected to the conductive metal construction,.and a receiving station composed of a telephone and means for connectingsaid telephone in parallel to a section of said conductive metalconstruction.

9. In the electric transmission of signs in subterranean mines, thecombination of the conventional conductive metal construction in mineservice with an electrostatically chargeable first conductor embeddedwithin the surface soil, an electrostatically chargeable secondconductor located within the mine and having a large surface capacitymeans for respectively connecting the ends of said conductive metalconstruction to said first and second conductors, a trans-.

mitting station comprising a primary coil, a microphone and a currentgenerator in circuit with said primary coil, and a secondary coilconnected to the conductive metal construction, and a receiving stationcomprising a telephone, and means for connecting said telephone inparallel to a section of said conductive metal construction.

10. In the electric transmission of signs in subterraneanmines, thecombination of the conventional metal structures in mine service thatextend along the mine-excavations, with means for electrostaticallycharging said structures, and with means for rendering said chargingperceptible at a point distant from the charging point.

11. In the electric transmission of signs in subterranean mines, thecombination of the conventional metal structures in mine service thatextend along the mine-excavations, whereby the rock-formations liningsaid excavations constitute an insulator for said structure, with meansfor electrostatically charging said structures, and with means forrendering said charging perceptible at a point distant from the chargpoint JOSE}? HEINRICH REINEKE. [Lo 8.]

Witnesses:

WILHDLM BRUNn, inn'r Nurse.

